Combined Heat and Power (CHP) is an efficient way of generating electric power and useful thermal energy from a single fuel source. CHP is already installed in many sites around the U.S., with others in the pipeline. One of these is Capital Hill in Washington, D.C., where a CHP plant will serve the US Capitol, Supreme Court, and Senate and House office buildings.

The U.S. Department of Energy is working with industry to meet President Obama’s goal of an additional 40 GW of CHP in the US by 2020, resulting in a cleaner environment and greater energy independence.

Katrina Pielli, the Acting CHP Deployment Lead from the Advanced Manufacturing Office at the U.S. Energy Department brings us up-to-date about the role of CHP in the US now and in the future.

Katrina Pielli (DOE): CHP is already an important resource for the U.S., with the existing 82 GW of CHP capacity representing over 12% of total MWh generated annually. CHP is well suited for certain market sectors including: hospitals, colleges and universities, as well as many industrial sector applications including the chemical, paper, and refining sectors. It can also benefit grid resilience and help keep critical infrastructure (hospitals, emergency shelters, and other such facilities) running during extreme weather events such as Superstorm Sandy.

However, recent market activity suggests that increased CHP development is being driven by lower cost domestic natural gas supplies, growing state and local government support, and changing market conditions for power and industrial sectors.

Combined Heat & Power can also benefit grid resilience and help keep critical infrastructure running during extreme weather events such as Superstorm Sandy.

What is the current status of CHP in the commercial building sector and what do you expect to happen?

Katrina Pielli (DOE): Between 2006-2011, there was over 350 megawatts (MW) of new CHP installed in the university and campus sectors, and nearly 150 MW of new CHP in the hospital sector. During the next five years, we expect to see increased CHP deployment in the commercial sector. Based on our estimates, there are 65 gigawatts (GW) of CHP technical potential in the commercial sector.

Widespread alreadyAs stated above by Katrina Pielli, CHP is already widespread in the American commercial buildings sector. A few examples in the U.S. include:

• Texas Medical Center, Houston: The largest medical center campus in the world housing 14 hospitals, 21 academic institutions, three medical schools and six nursing schools. A total of 48 MW of CHP is integrated in the campus, operating at efficiencies of 80%. The CHP system will reduce the Center’s carbon emissions by 75,000 tons annually and carbon dioxide emissions by more than 305,000 tons annually compared to a conventional system.

PHOTO: Texas Medical Center

• Cornell University, New York: A 30 MW CHP plant serves more than 250 campus buildings. The plant achieves an operating efficiency of 77% and supplies 85% of the electricity required. Carbon emissions have been reduced by 50,000 tons a year.

• The Rio Hotel, Las Vegas: 4.9 MW CHP system providing 50% of annual electricity needs and domestic hot water for space heating. Annual energy savings of USD 1,500,000 and a payback period of 5 years.

During the next five years, we expect to see increased CHP deployment in the commercial sector. Based on our estimates, there are 65 gigawatts (GW) of CHP technical potential in the commercial sector.

SectorsCHP plants can be broadly divided into three sectors: the electric power sector where they produce electricity for public sale; the industrial sector, where the CHP facility is usually intended to provide electricity and steam to a factory; and the commercial sector, where the CHP facility is most often used to provide electricity and heating and/or air conditioning on a college campus or building.

CHP is used or has the potential to be used in many areas, including:• Industrial and manufacturing operations• Military bases• Prisons• Nursing homes• Wastewater treatment facilities• Multi-family housing and residential communities.

To find out more about the technologies behind CHP and its future in the U.S, click on the tab "Future technologies - now" at the top of this story.

Future technologies - now

A range of technologies are available to power CHP facilities, and which is best suited is often a question of size. According to Katrina Pielli, the Acting CHP Deployment Lead from the Advanced Manufacturing Office at the U.S. Energy Department, different CHP technologies can be utilised.

Katrina Pielli (DOE): Both the commercial and industrial sectors utilise a range of CHP technologies that best fit the needs of each site and its energy use. In the commercial sector, reciprocating engines are often used. CHP systems tend to have improved economics at medium and large commercial buildings, where the average size of systems is around 10 MW. For smaller requirements, say 30 to 250 kW, microturbines may be better suited.

Other technologiesOther types of CHP technology include:

• Advanced Industrial Gas Turbines: For applications up to 20 MW, in which atmospheric air is compressed, heated, and then expanded, with the excess of power produced by the turbine over that consumed by the compressor used for power generation.

• Fuel cells: Provide an emissions free solution by producing direct current electricity through an electrochemical process, much like a standard battery, but using a fuel supply that continuously replenishes the fuel cell.

Future goalsAccording to Katrina Pielli the U.S. has laid down a goal of increasing its CHP capacity 50% by 2020. An Executive Order from 2012 calls for an additional 40 GW of new CHP by 2020, in addition to the 82 GW of CHP capacity already installed.

In your opinion, could CHP be viewed as part of a general trend towards increased sustainability in North America?

Katrina Pielli (DOE): CHP is seen as an energy efficiency measure. CHP applications operate at 65–75% efficiency, which is a large improvement over the national average of 45% for these services when separately provided. State policy makers, industrial companies and non-governmental organizations view it as an efficient and clean energy solution compared to separate heat and power generation. This greater efficiency leads to a number of benefits such as reduced energy costs and lower greenhouse gas emissions.

Saving ten billion U.S. DollarsU.S. Energy Department estimates show that meeting the goal would save the country an estimated 1 quadrillion Btu (quads) of fuel. That equals nearly 1% of all energy use in the U.S. In monetary terms, this could save energy users ten billion U.S. Dollars a year. CO2 emissions would also be reduced by 150 MMT (million metric tons) annually, equivalent to the emissions from over 25 million cars.